Data Logging With the OEM Pack

[Eli]

It's with the old weak pack.

Yeah, I'm not really sure what's going on. From what I've read, it was only the very first revision of the BCM that had this cold weather bug. I'll have to check, but I think the BCM I'm using is a couple of revisions in.. so maybe you're right.

Maybe I'll try putting in a late revision BCM to see if it still happens. It's nice being able to see IMA data without having to rely on the BCM Gauge now.

Overcharging a NiMH cell at a fraction of C isn't a big deal(like the 350mA grid charge), but high amperage(1C+) overcharging isn't a good thing. It does seem the car is pretty good at preventing any dangerous over or undercharge situation though, so maybe it's OK.

[Mike Dabrowski 2000]

I put a scope on the HV during one of those events, many years ago, and I recall that instead of a steady current, it was a sawtooth, so I am not sure if the OBDIIC&C current is the peak or average when that is happening?
I expect the pack PTC strips and the temperature sensors keep things from getting too hot, and from what I have seen, the temperature issues are the main reason that overcharging at higher currents are a problem.
Most NIMH and NICAD chargers for power tools charge at several amps until the temperature raises to a setpoint, and then just stop.
A look at these Prius subpacks
http://99mpg.com/blog/batterypacksex...appenstoapriu/
and one would have expected them to be toast, but I have been using that same set of two subpacks as my lawn tractor 12V battery for several years, and they work great.
Sit all winter, one grid charge in the spring, and a summer of use. My lawn is big, so when using the bagger I need to stop to empty the bags and restart the lawn tractor 20-30 times in an hour mowing, and the batteries crank the 13HP engine as well on the last start as on the first.
Tough little batteries.

[3-Wheeler]

Originally Posted by Mike Dabrowski 2000

I put a scope on the HV during one of those events, many years ago, and I recall that instead of a steady current, it was a sawtooth, so I am not sure if the OBDIIC&C current is the peak or average when that is happening? ....

Mike,

I would not be at all surprised that the waveforms between Assist and Regen are different.

This is because I put on a 200mV mini-voltmeter display in the dash to monitor pack voltage, with a custom voltage divider at the pack taps.

Anyway due to electrical noise, the meter only reads a steady voltage when the engine off during a FAS. At all other times, the meter fluctuates all over the place.

However that fluctuation is completely different when Regenning into the pack. The voltmeter refresh rate has got to be over 20Hz and you can see "patterns" in the display fluctuations during regenning that are not present at any other time when the engine is running.

Jim.

[Mike Dabrowski 2000]

Jim,
I have a real time DVM with a rotary switch to monitor all the taps as well as the full pack voltage. I get a nice steady voltage reading even when driving.

I used a 60 mhz storage scope to capture the regen waveforms. It was a sawtooth until the pack got over 40F then it was DC.

Nothing to do with Assist.